The present invention relates to a method of assembling a valve-lash adjuster, with adjusting a valve clearance in a valve mechanism for an automotive engine.
A valve lift mechanism which enables to change the valve lift by employing an eccentric rocker shaft is well known. Such a mechanism is generally provided with a valve-lash adjuster incorporated in a rocker arm. The lash adjuster has a piston outwardly urged by a spring so as to act as a shock absorber, which is disclosed in Japanese Patent Laid Open No. 62-35005. Referring to FIG. 6 showing a conventional valve-lash adjuster, a rocker arm 21 is provided with a bore 21a at an end, which has a shock absorbing spring 22 therein. A screw 23 is screwed in an upper portion of the bore 21a and secured thereto by a nut 24 for preventing the screw 23 from rotating. A piston 25 having a flange 25a, the underside of which engages a shoulder 21b formed in the bore 21a, is disposed in the lower portion of the bore 21a opposing the screw 23. Thus, the piston 25 elastically abuts on a top of a valve stem (not shown).
In the above-described conventional valve-lash adjuster, the screw 23 is screwed in the bore 21a to adjust the valve clearance after an elastic member such as the spring 22 had been inserted. In order to adjust the clearance for between the piston and the valve stem, a thickness gauge is inserted in the clearance, and the screw 23 is rotated. However, since the piston 25 is retracted into the bore 21a, compressing the spring 22, it is difficult to accurately adjust the clearance.